In the present state of the art of baling large rectangular bales, most balers employ a large plunger equal in size to the end dimensions of the bale. This plunger compresses the full volume of hay, comprised of the plunger dimensions multiplied by the thickness of the leaf of hay, in approximately 10% of the plunger's cycle time. This requires a large amount of horsepower during the time the plunger is actually compressing hay and therefore a flywheel is employed to even out the power requirements throughout the cycle of the plunger. The cyclical power requirements of the plunger also require the baler to have enough mass to hold the machine together to absorb the peak power requirement of the plunger.
A round baler can make a cylindrical bale of hay of approximately the same volume, density and rate as that of a square baler, however, the round baler can weigh up to 50% less as compared to a square baler due to the fact that it compresses the hay continuously. There have been a number of attempts to make a machine that would make a square bale of hay using some form of mechanism to continuously compress the hay into the final bale chamber. U.S. Pat. No. 4,490,968 by Jerome M. Cysewski attempted this by having a vertical bale chamber that rocked fore-and-aft over two stationary rollers. With this methodology, after the bale was formed, the bale would be tied off like a square baler and ejected similar to a round baler. Massey Corporation also attempted to make a continuous compression baler by having two rollers move vertically up and down the forward end of the bale in a stationary horizontal bale chamber. Neither of these methods proved to be an efficient or effective way to create a bale of hay. The problems with these methods included, but were not limited to, issues with feeding the hay to the compression rollers, tying off of the bale, the control of the mechanisms by the computer, and the momentum of the rocking bale chamber.
An additional problem in the prior art is found in the tying off process used in most square balers. Most large square balers require two knots per tying cycle because of the extreme back pressure needed for operation due to the cyclical compression of hay by the plunger. This extreme back pressure often causes the twine to slip out of the knotters so the next bale cannot be tied.